Fuel feed control mechanism



Jan. 2, 1940. i B. F. BOWER 2,185,686

FUEL REED comm. MECHANISM Filed Nov. 16, 1938 2 Sheets-Sheet 1 29fizz/6711 27:

' fiyrazz I .5 0 we?" 27 Q 33 //1Mz- Jan. 2, 1940. ow I 2,185,686

FUEL FEED CONTROL MECHANISM F iled Nov. 16, 1938 2 Sheets-Sheet 2 jyronJ 3021/67 22 Y yaw Patented Jan. 2, 1940 UNITED STATES FUEL FEED CONTROL.MEonANisM Byron F. Bower, St. Charles, IlL, assignor to; The

Howell Company, St. Charles, Ill., 21. corporation of IllinoisApplication November 16, 1938, ea; No. 240,721

9 Claims.

The present invention relates to furnaces, and particularly to the fuelfeeding mechanism by which coal or similar types of fuel are fed intothe fire box of the furnace. The present invention is particularlyapplicable to the pusher type of fuel feeding device wherein areciproeating pusher block is located in a coal hopper and acts toadvance fuel to an opening which leads to the furnace chamber. Althoughnot limited thereto, the present invention is par-- ticularly applicableto the spreader type of fuel feeding means by which coal is thrown intothe fire box and spread over the grates. The fuel throwing means may beof any suitable type, insofar as the present invention is concerned.

It is the purpose of the present invention to provide an improved meansfor adjusting the movement of the pusher to advance more or less coalwhere the driving unit for the pusher includes a motor or other suitablemeans operating it at a predetermined speed.

The present invention contemplates the provision in a fuel feedingmechanism of the type described of a rock shaft which is connected tothe pusher block and means for variably moving the rock shaft from aconstantly driven drive shaft. The contemplated means comprises two camarms, one of which drives the rock shaft in proportion to its movement,and the other of which is driven from the constantly moving shaft inproportion to its movement. The two cam arms have opposed cam surfacesreceding from each other toward the outer ends of said arms, and a campin member is movably mounted between the cam surfaces. Movement of thepin member preferably is controlled automatically from a suitable typeof commercial controller, such as those responsive to variations insteam pressure. A control arm which carries the cam pin member may bepre-set or adjusted for any particular requirement.

The present invention contemplates a control device of the characterdescribed wherein the separation of the opposed cam faces is calculatedto cooperatewith the damper controlling the flow of gases from thefurnace so that the amount of coal fed is varied in direct proportion tothe variation in damper opening.

It is a purpose of the present invention to provide a simple andeffective control mechanism comprising two opposed cam arms, one ofwhich is driven from the drive source, and the other of which drives therock shaft that actuates the coal pusher block wherein the two cam armsare limited as to separation and are adjustable as to their approach toeach other, the last named adjustment being manually or automaticallyoperated. r y

The features and advantages of the present invention will appear morefully as the description proceeds, reference being had to theaccompanying drawings wherein a preferred form of the invention isshown. It is to be understood, however, that the drawings anddescription are illustrative only and are not to be taken as limitingthe invention except insofar as it is limited by the claims.- I

In the drawings, Fig.- 1 is a fragmentary sectional View taken throughthe lower part of a coal hopper and through the coal feeding mechanismby which coal is advanced to a furnace and thrown into the fire box ofthe furnace;

- Fig. 2 is a view inside elevation of the mechanism employed to operatethe pusher block which feeds the fuel from the hopper;

Fig. 3 is a fragmentary plan view showing the mechanism illustrated inside elevation in Fig. 2;

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 2, and

.Fig. 5 is a fragmentary sectional View taken on the line 5-5 of Fig. 2.I Referring now to the drawings, the present invention is embodied inthe fuel feeding mechanism of a furnace that burns coal, coke, or asimilar fuel. In the device as shown, the numeral l0 indicates the frontwall of a furnace to which there is bolted a door casting H. The doorcasting H supports a framework l2 that carries a mechanical" spreaderfor throwing coal into the fire box of the furnace and spreading it overthe grates therein; The details of the mechanism for spreading are notclaimed herein, but for the purpose of understanding they will. bedescribed briefly. The mechanical spreader com prises a rotating shaftl3 which carries a number of spreader'paddle's such as indicated at Mand 15. These paddles strike coal that falls into a deflector housingHi. The coal is stored in a hopper l1 and is fed from this hopper bymeans of a pusher block I8 located in the bottom of the hopper. Thepusher block 18 rides on a base plate 19 which projects over thedeflector housing 16 as indicated at Zil. An agitator bar 2t forms apart of the pusher block I8 for working the coaldown in front of thepusher block sothat it. can be advanced over the projection 20 of .thebase plate IS.

-The means for operating the pusher block I8 comprises an arm 22 and arock shaft 23 which is driven from a suitable source of power. Thepresent invention concerns itself with the means for operating the rockshaft 23 from a continuously driven shaft, or motor, or other source ofpower.

Referring now to Figs. 2-5 inclusive, the rock shaft 23 is provided witha cam arm 24 which is keyed to the shaft 23 by a suitable key 25. Asecond cam arm 26 has a hub portion 21 which is journalled on the shaft23 between two hub portions 28 and 29 of the cam arm 24. The portions 28and 23 act as a guide for the hub 2'! of the cam arm 26. The two camarms 24 and 26 are held against separating by means of a latch 30 whichhas two cars 3| and 32 projecting down over the upper end of the cam arm24 and pivoted to the cam arm 24 by a shaft 33. The latch 30 has a hook34 at its free end, and this hook engages a catch portion 35 at the topof the cam arm 26. The upper end of the cam arm 26 is rounded as shownat 36 so that the latch 30 will ride on this upper end as the cam arm 26moves toward and away from the cam arm 24.

Thecam arm 26 is driven from a drive shaft 31 which is operated from asuitable motor, not shown. This motor is preferably the same motor whichdrives the rotor shaft 13. The shaft 37 has an eccentric 38 thereon. Anarm 39 has a hub 46 journalled on the eccentric 38. The other end of thearm 39 is bifurcated to provide two spaced hub portions 4| and 42 thatreceive the cam arm 26 between them. A shaft 43 connects the cam arm 26with the hub portions 4| and 42. p

The cam arms 24 and'26 have opposed cam faces 44 and 46 which cam facesare adapted to be held apart by a cam pin 45. It will be evident from aninspection of Fig. 2 that as the pin 45 moves upwardly from the positionshown in full lines in Fig. 2 to the position shown in dotted lines inFig. 2, the cam arm 26 will be permitted to move more relative to thecam arm 24 without effecting any movement of the cam arm 24. When thepin 45 is in the position shown in full lines in Fig. 2, no movement ofthe cam arm 26 is permitted toward the cam arm 24. The two arms mustmove together. Now, however, as the pin 45 is lifted, it fails to bridgethe gap between the faces 44 and 46. Therefore, the cam arm 26, when itis moving toward the cam arm 24, will first take up the space be- Itween the faces 44 and 46 that is in excess of the diameter of the pin45. When this space is all taken up, then the two arms will be caused tomove in unison. Then upon the return movement of the cam arm 26 the twocam arms will separate until the hook 34 on the latch 30 engages thecatch 35 on the cam arm 26. Vertical adjustment of the pin 45 can thusbe made to take care of the angular movement imparted to the cam arm 24and, therefore, the angular movement imparted to the shaft 23.

In order to control the position of the pin 45, this pin is suspended byintegral links 4! and 48 from a control lever 49. The control lever 49has a hub portion 50 which is journalled upon a pin 5!. Two arms 52 and53 project from the hub 56 and are bifurcated at their free ends, asshown at 54 and 55 to receive the links 4! and 48. Pins 56 and 5'!pivotally mount the links 41 and 48 in the bifurcated ends 54 and 55.

The control lever 49 has a bifurcated end portion 58 which is adapted tobe connected to a control link 59 leading to a suitable type ofcommercial controller, steam responsive or otherwise.

As is common with controllers of this character, they adjust the damperopening and the coal feed and air supply in response to some regulatingfactor such as the steam pressure in the boiler.

In order to manually control the coal feed and to adjust it properly forthe automatic operation, I mount the pin 5| on a hand lever 60.

The hand lever 60 is pivoted on a stub shaft 6|. The hand lever isprovided with a laterally extending ear 62 having an elongated slot 63that receives a screw threaded stud 64. A clamping nut 65 having a handgrip 66 is provided for r clamping the ear 62 against the side wall ofthe '15 framework I2. I

It is believed to be evident that by vertically adjusting thehand lever60 the position of the pin 45 can be varied to suit any particularoper-- ating conditions. In fact, it can beused to move the pin upso farthat movement of the arm 24 inresponse to movement of the cam arm 26practically ceases. This would mean that even though the shaft 31continued to operate, the pusher 56 would cease to feed coal and therotor 83 would receive no coal. The design-of the cam faces 44 and 46 iscalculated to produce a variation in coal fed which is proportional tothe variation in damper opening as the damper is opened and closed inunison with vertical movement of the pin 45.

The simplicity of the control mechanism hereinbefore described does notlimit its flexibility since it is possible with the simple adjustmentsof the lever arm 66 to vary the stroke of the pusher l8 from maximumstroke to practically no movement at all. There are no set screws toadjust, and the range of movement of the pin45 is sufficiently great tomake the manual adjustment thereof sensitive enough for all operatingconditions."

From the foregoing description it is believed on said rock shaft, asecond cam arm pivoted on said rock shaft, said arms having opposed camfaces, means for rocking said pivoted cam arm through a predeterminedarc, and means for variably rocking the first named cam arm' in responseto the movement of the pivoted cam arm, said means comprising a latchsecured on one arm and hooked over a catch on the other arm to limit thespreading of said arms and a cam pin interposed between said cam facesand movable lengthwise with respect to said faces to vary the limit ofapproach of the pivoted arm to the arm fixed on the rock shaft.

2. In a fuel feeding mechanism for furnaces, a

rock shaft, means for operating said rock shaft,

said means comprising a cam arm fixed to said rock shaft, a second camarm pivoted on said rock shaft, said two cam arms having opposed camsurfaces, a member interposed between said cam surfaces, means formoving said member toward and away from the rock shaft, means limitingthe angular separation of said cam arms, and

power driven means rocking said pivoted cam arm.

3. In a fuel feeding mechanismv for furnaces, a rock shaft, means foroperating said rock shaft, said means comprising a cam arm fixed to saidrock shaft, a second cam arm pivoted on said rock shaft, said two camarms having opposed cam surfaces, a member interposed between said camsurfaces, a control lever for moving said member toward and away fromthe rock shaft, means limiting the angular separation of said. cam arms,and power driven means rocking said pivoted cam arm.

4. In a fuel feeding mechanism for furnaces, a rock shaft, means foroperating said rock shaft, said means comprising a cam arm fixed to saidrock shaft, a second cam arm pivoted on said rock shaft, said two camarms having opposed cam surfaces, a member interposed between said camsurfaces, acontrol lever connected to said member for moving said membertoward and away from the rock shaft, manually adjustable meanssupporting said control lever, means limiting the angular separation ofsaid cam arms, and power driven means rocking said pivoted cam arm.

5. In a fuel feeding mechanism for furnaces, a rock shaft, means foroperating said rock shaft, said means comprising a cam arm fixed to saidrock shaft, a second cam arm pivoted on said rock shaft, said two camarms having opposed cam surfaces, a member interposed. between said camsurfaces, a control means connected to said memher for moving saidmember toward and away from the rock shaft, a manually adjustable lever,said control means being movably mounted on said manually adjustablelever, means limiting the angular separation of said cam arms, and powerdriven means rocking said pivoted cam arm.

6. In a fuel feeding mechanism for furnaces, a rock shaft, means foroperating said rock shaft, said means comprising a cam arm fixed to saidrock shaft, a second cam arm pivoted on said rock shaft, said two camarms having opposed cam surfaces, a member interposed between said camsurfaces, a control lever for moving said member toward and away fromthe rock shaft, a manually adjustable lever, said control lever beingpivoted on said manually adjustable lever, means limiting the angularseparation of said cam arms, and power driven means rocking said pivotedcam arm.

7. In a stoker, a rock shaft and drive means for said rock shaft, saiddrive means comprising a cam arm fixed on said rock shaft, a second camarm pivoted on said rock shaft, said arms having opposed cam faces'meansfor rocking said pivoted cam arm through a predetermined arc, and meansconnecting said arms for variably transmitting the rocking motion of thepivoted cam arm to the first named arm, said last named means comprisinga bearing member suspended between said cam faces and adjustablelengthwise thereof.

8. In a stoker, a rock shaft and means for operating said rock shaft,said means comprising an arm connected to said rock shaft, a second armmovable toward and away from said first named arm and pivoted on saidrock shaft, means for rocking said second arm and means connecting saidarms for variably transmitting the rocking motion of the second arm tothe first arm, said last named means including cam surfaces on said armsand an adjustable control means engaging said cam surfaces and movablelengthwise thereof for variably limiting the movement of one of saidsurfaces relative to the other.

9. In a stoker, a rock shaft, a drive shaft, an arm connected to'saidrock shaft, a second arm for actuating said first named arm, aneccentric on said drive shaft, a link connecting said eccentrio withsaid second arm, means limiting the separation of said arms, andadjustable means limiting the approach of said second arm to the firstarm, said adjustable means comprising a pin interposed between said armsand movable lengthwise thereof, and cam faces on said arms for engagingsaid pin. 1 1

BYRON F. BOVVER.

